Process of making ball seats



May 28, 1929.

` F. c. CRAWFORD ET AL. 1,714,660 y Filed April 24, 1925 Patented May 28, 1929.

FREDERICK c. CRAWFORD AND MATTHEW r. GRAHAM, or DETROIT, MTCHIGAN, As-

SIGNORS TO THOMPSON PRODUCTS INC., OF OLEVELAND, OHIO,

or oHro.

A CORI?ORATION` PROCESS OF MAKING BALL SEATS.

Application filed April 24, 1926.v Serial No. 104,400.

The invention relates to a process for making ball seats adapted to serve as a bearing member for the ball of a ball stud, such as are commonly used in drag-links for automobiles. Such a ball stud consists of a substantially spherical enlargement on the end of a short shank, and, in use, the spherical enlargement engages onev or moreof such ball seats to serve as a bearing surface therefor.

Heretofore it has been the general practice to make such ball seats on what is commonly known as a screw machine from a solid rod of metal, which necessitates the employment of somewhat costly machinery, consumes a considerable time, and results Vin considerable loss of metal.

l't is the object of this invention to simplify the process, speed production, and effect a saving in costof the articles produced.

Accordingly we construct the article from a metal plate and usesuch pressing, forging or stamping operations as to leave comparatively little machine work to be done.

The invention consists of the process hereinafter, described and .claimed by which a steel disk is formed into a ball seat.

ln the accompanying drawings, illustratingthe steps of our process:

Figure l is a plan of a circular disk blank from which the ball seat is made;

Fig. 2 is a section thereof;

Fig. 8 is a view illustrating a die and punch with the blank disk positioned over the die for the first operation;

Fig. 4 is a view at the end of this operation showing the metal disk forced by the punch into the die,.causing the metal blank to be pressed into concave-convex form;

Fig. 5 is a face view of the blank formed by the pressing operation;

Fig. 6 is a section thereof;

Figs. 7 and 8 are, respectively, a face view and a section of the blank after completion of the succeeding operation which' consists in trimming away an annular portion from the outer margin of the partially formed blank shown in Figs. 5 and 6 on the line a of these figures;

Figs. 9 and l0 are, respectively, a face and a sectional View at the end of a succeeding operation consisting in coin pressing the blank shown in Figures 7 and 8 to form the plane base of the ball seat;

Figs. ll and 12 are, respectively, a plan and a side elevation of thek blank shown in' Figs. 9 and l0 after the succeeding operation, which consists in forming a notch in the wall of the ball seat. r

Referring to the drawings in. detail, in which the same reference numeral is used throughout-to designate the same part, the process is begun with a steel disk l, formed inv any well known way, such as by punching from a metal plate. As it is desired to form the metal cold, the plate selected is preferably one made of low carbon annealed steel made especially for heavy pressing or deep drawing work. The first step is to center the disk l over a die 2 and subject it to `heavy pressure from a punch 3.` The die 2 is preferably` concave and hemispherical, as indicated, and the end 3a of the punch is convex and hemispherical, the radius of curvature ofthe end of the punch being equal to the radius of the die less the thickness of the blank. The relation of the parts at the beginning ofthis operation is shown in Fig. 3 and their relation at the end of the first step is shown in Fig. 4, While Figs. V5 and 6 show the blank, so formed, in face view and vertical section. The result of the first step is that the blank is formed into a hemispherical shell having a concave spherical inner surfaced and a con- Vex outer spherical surface 5.

The partially formed blank is next subliected to a shearing or machining operation by which an annulus of metal is removed from the outer margin thereof along the Vsurface of a cylinder coaxial with the formed blank as -indicated by lines (L in Figs. 5 and 6. As a result' of this operation, the blank takes the form indicated in Figs. 7 and 8. In this form it might be utilized as a bearing for a ball stud under some circuinstances,-but ordinarily the convex surface 5 could not be properly seated. In order to provide such a seat it is necessary to subject the blank to another operation to'provide a plane, instead of a curved surface. This is effected in any suitable way, as 'by removing, by machining, the convex surface up to the plane indicated vby line b of Fig. 8, or by coinpressing the partially'formed blank of Fig. 8 to the form shown in Fig. l0, which provides a fiat base 6 to seat against a suitable abut* ment. Coin-pressing is effected by forcing the blank shown in Fig. 8 intoa female die having the desired form of the completed article.

VInstead of following the steps above'inwaa...

dicated the arti-cle shown in Fig. l0 might be formed from the disk l in a single pressing or forging operation. To this end a smaller blank would be selected, and instead of forcing it into a die of spherical curvature a die made to conform to the plane or coinpressed end 6, shown in Figure 10, would be provided. Using the same form of punch as before de'- scribed, i. e., one with a hemispherical end, the same would be caused to force the blank into the die with such pressure that the'metal would flow to form the base 6 shown in Fig.

The product formed as shown in Fig. l0, is substantially the same as the product made with the well known screw machine. Inorder to give the product v,so `formed the hardness and smoothness desirable for a good bearing surface and to enhance its appearance, it is preferable to subject it to the further Well known steps of hardening and grinding.

The ball seat asshown in Fig. 10 may be used in situations where the shank of the ball -stud projects outwardly or away from the base 6; but in many situations it is necessary that the shank of theball stud shall lie parallel to the base 6. In such case it is necessary to perform another operation on the part as shown in Fig. 12, which consists in cutting a semi-circular notch 7 in the wall, to a depth less than the depth of the bearing surface, thereby affording a shoulder to prevent escape of the ball while permitting the shank of the ball stud to extend therethrough. It will be apparent from the abovel description, thatwe have devised a process for making ball seats which will economize ma* terial and cheapen the cost of production.

`The details of the process may be varied semi-spherical surfaces, and reducing the diameter of said cup member by trimming away an annular portion `of the member yto form an exterior cylindricalsurface on and substantially coaxial vwith said member.

2. The process of making a bearing member, which consists in forming a substantially liat metal disk into a cup member having substantially concentric interior and* exterior semi-spherical surfaces, reducing the diameter of said cup member byltrimming away an annular portion of the `member L.to form an exterior cylindrical surface on and substantially coa-Xiall with -said member, and thereafter cutting a transverse notch in said member shaped to receive the shank of a ball stud.

Signed by4 us this 16th day of April, 1926.

FREDERICK C. CRAWFORD. MATTHEW P. GRAHAM. 

